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APPROACH TO CYANOTIC CONGENITAL HEART DISEASE IN THE NEWBORN
By Christopher Cheung, MD 2013
Reviewed by: Santokh Dhillon, MD, MBBS
INTRODUCTION TO CYANOSIS
Cyanosis is a bluish or purple discoloration of the skin and mucous membranes associated with
poor oxygenation. It is noticeable when >5 g/dL of deoxygenated hemoglobin is present and
usually assessed by pulse oximetry. It is very difficult to detect unless the arterial saturation is ≤
85% and best seen in tongue and oral mucosa. Acrocyanosis (cyanosis only in peripheral parts),
commonly seen with cold environments or after bathing, is always a normal finding and is not a
true cyanosis. Long standing cyanosis results in digital clubbing.
Causes of Cyanosis: Cardiac and Non-Cardiac
Non-Cardiac Causes of Neonatal Cyanosis
Pulmonary
Hyaline membrane disease
Meconium aspiration/Pneumonia
Pneumothorax/Pleural effusion
Persistent pulmonary hypertension of the
newborn
Choanal atresia or stenosis
Diaphragmatic hernia
Neurologic
CNS dysfunction
Respiratory neuromuscular dysfunction
Heavy maternal sedation
Perinatal asphyxia
Intrauterine fetal distress
Please note that an in-depth approach to neonatal cyanosis is available on LearnPediatrics.com
Cardiac causes of cyanosis can be divided into ductal-dependent and ductal-independent lesions.
Ductal-dependent lesions require the ductus arteriosus for adequate pulmonary circulation and
include: Tetralogy of Fallot, tricuspid atresia or Ebstein’s anomaly, and pulmonic atresia or
stenosis. Ductal-independent lesions result in pulmonary and systemic mixing leading to
deoxygenating of the arterial blood; hence cyanosis. These lesions include: truncus arteriosus,
transposition of the great arteries, and total anomalous pulmonary venous connection. In these
conditions, mixing typically occurs through an atrial septal defect (ASD), patent foramen ovale
(PFO), or ventricular septal defect (VSD).
Differentiating Cyanotic Congenital Heart Lesions
Ductal-dependent lesions
Tetralogy of Fallot
Tricuspid atresia or Ebstein’s anomaly
Pulmonic atresia or stenosis
Ductal-independent lesions
Truncus arteriosus
Transposition of the great arteries
Total anomalous pulmonary venous return
Hypoplastic left heart syndrome
HISTORY TAKING: KEY SYMPTOMS
A thorough cardiac history including prenatal, perinatal and family history should be taken. For
older children history of a heart murmur, respiratory distress and exercise intolerance is helpful.
Important flags on history include:
Cyanosis
-
Timing and location (peripheral or central) of cyanosis, clubbing
-
Refractory cyanosis if fails to improve with oxygen therapy
Fainting or cyanotic spells
-
Cyanosis occurring with exertion, emotions, and/or bearing down, indicative of dynamic
and increasing right ventricular outflow tract obstruction, which results in increased rightto-left shunting through intracardiac shunt (VSD, ASD)
Exercise Intolerance
-
History of exercise intolerance, including dyspnea and/or diaphoresis on minor exertion,
or palpitations with exertion
Gestational History and Family History
-
Prenatal screening is important as many genetic syndromes are associated with congenital
cardiac malformations
-
Maternal illness: diabetes, rubella, teratogenic medications.
-
More recently, mothers or fetuses at-risk for congenital cardiac malformations usually
require a fetal echocardiogram to investigate for cardiac defects
-
Family history of congenital cardiac disease is important, as more and more individuals
with congenital heart disease are living into their reproductive age.
Please note that an approach to cardiac history taking is available on LearnPediatrics.com
PHYSICAL EXAMINATION: KEY FINDINGS
A thorough physical examination should be performed, including complete cardiac and
respiratory examination. Of note, important findings include:
Inspection
-
Dysmorphic features of genetic/congenital malformations (ie. Down’s syndrome is
associated with endocardial cushion defects, Turner’s syndrome associated with
coarctation of aorta)
-
Look for the signs of peripheral (nail beds) and central (mucous membranes) cyanosis
-
Differential cyanosis (oxygen saturation in lower limbs < upper limbs)
Cardiac Examination
-
Heart rate, pulse oximetry, palpate central and peripheral pulses and/or measure blood
pressure in upper and lower extremities
-
Palpate for loud heart sounds, parasternal heave, apical impulse and thrill.
-
Auscultate for abnormal (ie. single or widely split S2) and extra heart sounds and
murmurs (Grade, timing, location, radiation, intensity and maneuvers)
-
Signs of heart failure: parasternal heave and palpable P2 (pulmonary hypertension),
elevated JVP, hepatomegaly, and peripheral edema (right-sided failure), displaced apical
impulse (enlarged LV)
Respiratory Examination
-
Observe for signs of respiratory distress like tachypnea, dyspnea (ie. accessory muscles,
paradoxic diaphragm) and hypoventilation
-
Palpate for asymmetric diaphragmatic expansion, and in older children percussion for
consolidation, pleural effusions, and pneumothorax
-
Auscultate for air entry, listen for rales/crackles (consistent with effusions and/or
consolidation)
-
Congestive heart failure: Poor air entry and dullness to percussion at the bases (pleural
effusion), along with basal rales/crackles (pulmonary edema)
Please note that an approach to murmurs is available on LearnPediatrics.com
INVESTIGATIONS FOR CYANOTIC CONGENITAL HEART DISEASE
If cyanotic heart disease is suspected, the following investigations are available for confirmation
of underlying diagnosis:
Electrocardiogram (ECG)
Right ventricular hypertrophy: transposition of great arteries, total anomalous pulmonary venous
return, tetralogy of fallot, double-outlet right ventricle, PPHN
Left or bi-ventricular hypertrophy: truncus arteriosus, transposition of great arteries, pulmonary
or tricuspid atresia, asplenia syndrome
Right bundle branch block: Ebstein’s anomaly
Chest X-ray (CXR)
Chest x-ray will demonstrate cardiac size and pulmonary vascularity.
Cyanotic cardiac lesions with increased vascularity include simple TGA, TAPVR, DORV, and
polysplenia syndrome.
Cyanotic cardiac lesions with decreased vascularity include TOF, complex TGA, Ebstein’s
anomaly, pulmonary and tricuspid atresia, and asplenia syndrome.
Certain unique chest x-ray findings might be more helpful and include:
“Egg-shaped” heart transposition of great arteries
“Snowman” in total anomalous pulmonary venous return
“Boot-shaped” heart in Tetralogy of Fallot
Extreme cardiomegaly can occur in Ebstein’s anomaly
Hyperoxia Test:
Hyperoxia test is performed to demonstrate the response of the neonate’s arterial PaO2 to 100%
oxygen. Typically, if the cause for cyanosis is non-cardiac, the arterial PaO2 will increase to ≥
100 mmHg on exposer to 100% oxygen. However, if there is a cardiac cause for cyanosis, the
PaO2 will remain below 100mmHg.
Pre-ductal and Post-ductal Pulse Oximetry:
Pulse oximetry from the upper (pre-ductal) and lower/umbilical (post-ductal) arteries can help
identify a right-to-left shunt occurring through the ductus arteriosus. Typically, a difference of >
5% in the presence of normal oxygen saturation in upper limbs pre- and post-ductal
measurements suggests a right-to-left shunt. Furthermore, differential cyanosis (ie. cyanotic in
the lower extremities) is a manifestation of an extreme pre- to post-ductal PaO2 gradient, which
can occur in PPHN with interrupted aortic arch, and coarctation of the aorta. Of interest, reverse
cyanosis in the upper but not lower extremities could be a manifestation of an aortic coarctation
or interruption with concurrent transposition of the great arteries.
Transthoracic Echocardiogram (TTE)
A transthoracic echocardiogram will accurate identify a congenital cardiac lesion causing the
cyanosis. For example, two-dimensional echocardiogram can identify anatomical lesions like
septal defects (atrial or ventricular), tetralogy of Fallot etc. The additional spectral Doppler can
determine degree and direction of shunt and the grading of outflow tract obstructions.
Additional Modalities
Additional imaging modalities include cardiac catheterization and cardiac magnetic resonance to
further clarify abnormal anatomy in preparation for cardiac surgery.
SUMMARY OF CYANOTIC CONGENITAL HEART DEFECTS
Here, we present a brief summary of the pathophysiology of common congenital heart defects.
For an in-depth summary of congenital heart defects, consider reading Pediatric Cardiology for
Practitioners by Myung K. Park.
Transposition of the Great Arteries
In transposition of the great arteries, the aorta arises from the right ventricle while the main
pulmonary artery arises from the left ventricle. The systemic and pulmonary circulations run in
parallel with significant cyanosis occurring shortly after birth. As a result, most newborns are
dependent on a patent ductus arteriosus or ventricular septal defect (30-40% of cases) to maintain
appropriate oxygen saturations. Most of the children with this condition now a day managed with
arterial switch operation (aorta is connected to left ventricle and pulmonary artery to right
ventricle) along with correction of associate lesions like closure of ventricular septal defect.
Tetralogy of Fallot
Tetralogy of Fallot is the constellation of four congenital cardiac lesions, including: right
ventricular outflow tract obstruction (pulmonary infundibular stenosis), overriding aorta,
ventricular septal defect, and right ventricular hypertrophy. There is a resulting variable right-toleft shunt of deoxygenated blood, due to the dynamic right ventricular outflow tract obstruction.
Typically, infants present with cyanosis shortly after birth or cyanotic spells “tet spells” with
crying, exertion resulting in frequent squatting. Importantly, a variation of Tetralogy of Fallot
with pulmonary atresia will result in severe cyanosis immediately at birth. Most of the patients
are surgically repaired around 4-6 months of age.
Total or partial Anomalous Pulmonary Venous Return (TAPVR or PAPVR):
In this condition, the pulmonary veins have abnormal connection or drainage into systemic veins
resulting in volume overloading of the heart. Infants with TAPVR (all the pulmonary veins) may
present with symptoms of heart failure or with severe cyanosis and pulmonary hypertension if
obstructed. Anomalous pulmonary venous drainage can be divided into: Supracardiac (superior
vena cava), cardiac (coronary sinus, right atrium), infracardiac (portal vein, hepatic vein, inferior
vena cava), and a mixed drainage. Obstructed TAPVR requires urgent surgery.
Tricuspid or Pulmonic Atresia
The presence of tricuspid or pulmonic atresia typically requires a concurrent abnormality, such as
an atrial or ventricular septal defect and/or patent ductus arteriosus for survival. Infants present
with cyanosis and require surgical treatment.
Ebstein’s Anomaly
Ebstein’s anomaly involves the displacement of the septal and posterior leaflets of the tricuspid
valve into the right ventricle, resulting in severe tricuspid regurgitation and functional right
ventricular hypoplasia. There is a resultant dilatation of the right atrium, which can be seen on
chest x-ray. Treatment is usually surgical depending upon the severity.
Hypoplastic Left Heart Syndrome
Hypoplasia of the left ventricle results in a small and non-functional left ventricle to sustain
systemic circulation. Although tolerated in utero due to right ventricular compensation, the
hypoplastic left ventricle is unable to maintain adequate systemic flow after birth. Usually ductus
arteriosus is kept patent with prostaglandins till staged surgical palliation (Norwood operations)
is performed and followed by separation of systemic and pulmonary circulation with Fontan
operation.
Truncus Arteriosus
A persistent truncus arteriosus arises from the early fetal truncus, a single arterial trunk that gives
rise to both the pulmonary and systemic circulation. If this single arterial trunk fails to separate,
there remains a single outflow tract from the right and left ventricles, with a truncal valve. This is
usually associated with VSD.
Double-Outlet Right Ventricle
A double-outlet right ventricle simply means both the aorta and pulmonary artery arise from the
right ventricle, and the left ventricle outlet is through a large VSD. Patients may present with
either heart failure or severe cyanosis. This condition is repaired with different types of surgery
depending upon other associated lesion.
Heterotaxy: Asplenia (right atrial isomerism) and Polysplenia (Left atrial isomerism) Syndromes
Heterotaxia refers to the failure of differentiation between the right- and left-sided organ, which
results in not only complex cardiac lesions but also many other non-cardiac malformations
especially abdominal organs. These two syndromes are most accurately summarized and
compared in the following table:
Cardiovascular
Spleen
Lungs
Liver
ASPLENIA
Bilateral SVC, anomalous pulmonary
venous return, absence of the
coronary sinus, endocardial cushion
defect, pulmonary stenosis,
transposition of great arteries,
Splenic agenesis (**infection risk**)
Trilobated lungs with eparterial
bronchus
Midline liver, independent hepatic
vein on the opposite side of the IVC
Gastrointestinal Right-sided or midline stomach,
gastrointestinal malrotation
Eisenmenger’s Syndrome:
POLYSPLENIA
Interrupted inferior vena cava with
azygos continuation, pulmonic
stenosis, aortic stenosis or
coarctation, endocardial cushion
defects
Multiple but nonfunctional splenules
Bilobated lungs with hyparterial
bronchus
Usually normal but may be Midline,
Direct drainage of hepatic veins into
atrium
Malrotation or biliary abnormalities
Eisenmenger’s syndrome is cyanosis due to right-to-left shunting intracardiac shunt. Acyanotic
lesions (such as atrial or ventricular septal defects) are typically able to maintain appropriate
oxygen saturations despite a left-to-right shunt. However, persistent left-to-right shunting over
time causes pulmonary overcirculation resulting in increased pulmonary vascular resistance.
Pulmonary vascular resistance increases to a point where right-sided pressures become greater
than left-sided pressures leading to right-to-left shunt (shunt reversal) causing cyanosis. Signs of
Eisenmenger’s syndrome, apart from central cyanosis, include the findings of pulmonary
hypertension and right-sided heart failure such as right ventricular heave, palpable P2, pulmonic
or tricuspid regurgitation, elevated JVP, hepatic congestion/palpable liver, and peripheral edema.
MANAGEMENT OF CYANOTIC CONGENITAL HEART DISEASE
The following is a brief summary of acute and long term management of cyanotic congenital
heart disease. For an in-depth approach to managing specific congenital lesions, consider reading
Pediatric Cardiology for Practitioners by Myung K. Park.
Medical Management
Apart from supplemental oxygen, medical management of cyanotic heart diseases includes
prostaglandin E1 infusion in ductal-dependent lesions to maintain a patent ductus arteriosus. This
will usually serve as a bridging therapy towards intervention or cardiac surgery.
Atrial Septostomy
In cases of life-threatening cyanosis and/or pulmonary hypertension, a balloon atrial septostomy
is done by threading a wire through the foramen ovale, and inflating a balloon to open the
foramen ovale. This allows adequate mixing in the case of transposition of the great arteries, and
relieves right-sided pressures in the setting of pulmonary hypertension.
Cardiac Surgery
A number of surgical procedures can either correct congenital anomalies, or stabilize an infant
with congenital abnormalities. These palliative procedures can often serve as long-term options,
and include Blalock-Taussig shunt, Glenn procedure, and others.
GLOBAL REFERENCES
1. Park, MK. Pediatric Cardiology for Practitioners. 5th Edition. Philadelphia: Mosby
Elsevier; 2008.
ADDITIONAL REFERENCES
1. Park, MK. The Pediatric Cardiology Handbook. 4th Edition. Philadelphia: Mosby
Elsevier; 2010.
2. Rose V,Izukawa T, Moës CA. Syndromes of asplenia and polysplenia. A review of
cardiac and non-cardiac malformations in 60 cases withspecial reference to diagnosis and
prognosis. Br Heart J. 1975 August; 37(8): 840–852.
3. Marton T, Cesko I, Hajdu J et al. Heterotaxy syndrome, analysis of 13 cases and review
of the literature. Orv Hetil. 2002 Feb 10; 143(6):299-301.
4. Cesko I, Hajdu J, Marton T, Tarnai L, Zs Toth E. Familial heterotaxy syndrome. Case
report and review of the international. Literature. Orv Hetil. 1998 Nov 15; 139(46):27758.
5. Leite, J. Asplenia-polysplenia syndromes. 2006 [updated 2006 Jan 18; cited 2012 Dec 1].
Available from: www.thefetus.net.
6. Vonder Muhll I. Cyanotic Heart Disease and Eisenmenger’s Syndrome. Edmonton: The
University of Alberta; 2011 [updated 2011 Sep 9; cited 2012 Dec 1]. Available from:
www.medicine.med.ualberta.ca.